A premature infant born at 28 weeks gestation develops tachypnea, grunting, intercostal retractions, and nasal flaring within 30 minutes of birth. Chest radiography reveals diffuse bilateral 'ground-glass' reticulogranular infiltrates with prominent air bronchograms. What is the primary underlying pathophysiology?
Answer and explanation
Correct answer: D. Deficiency of pulmonary surfactant producing alveolar collapse
- Step 1: Neonatal Respiratory Distress Syndrome (RDS) is caused by developmental deficiency of surfactant produced by type II pneumocytes.
- Step 2: Surfactant deficiency raises alveolar surface tension, leading to widespread microatelectasis and ventilation-perfusion mismatch.
Answer
Deficiency of pulmonary surfactant producing alveolar collapse.
Why not the others: 'Delayed clearance of fetal alveolar fluid' describes transient tachypnea of the newborn (TTN), typical of term infants delivered via cesarean section; 'Meconium aspiration causing chemical pneumonitis' occurs in post-term infants with meconium-stained liquor; 'Congenital diaphragmatic hernia' shows bowel loops in the hemithorax with a scaphoid abdomen.
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